2,2,2-三硝基乙基-N-硝基甲胺的热安全性

为评价2,2,2-三硝基乙基-N-硝基甲胺(TNMA)的热安全性, 得到计算TNMA热安全性参数用的基本数据, 用经验式估算了TNMA的比热容(C_p)和热导率(λ). 用键能贡献于生成热Q_f的加和法, 估算了TNMA的标准生成焓Δ_cH_m^θ(TNMA, s, 298.15 K). 用热力学公式计算了TNMA的标准燃烧焓ΔU_m^θ(TNMA, s, 298.15 K)和标准燃烧能Δ_cH_m^θ(TNMA, s, 298.15 K). 用Kamlet-Jacobs 公式估算了爆速、爆压和爆热. 用经验式估算了分解热(Q_d). 通过差示扫描量热(DSC)曲线和高灵敏度布鲁顿玻璃薄膜压力计测得的逸出气体标准体积(V_H)-时间(t)曲线, 得到了TNMA放热分解反应的动力学参数. 用上述基本数据得到了评价TNMA的热安全性参数: 自加速分解温度(T_SADT), 热爆炸临界温度(T_be0和T_bp0), 绝热至爆时间(t_TIad), 撞击感度50%落高(H₅₀), 热点起爆临界温度(T_cr), 被300 K环境包围的半厚和半径为1 m的无限大平板、无限长圆柱和球形TNMA的热感度概率密度函数S(T), 相应于S(T)-T关系曲线最大值的峰温(T_S(T)max), 安全度(SD), 临界热爆炸环境温度(T_acr)和热爆炸概率(P_TE). 结果表明: (1) TNMA有较好的热安全性和对热抵抗能力, 与环三亚甲基三硝胺(RDX)相比, TNMA易从热分解过渡到热爆炸; (2) 不同形状大药量TNMA 热安全性降低的次序为: 球>无限长圆柱>无限大平板; (3)TNMA有高的燃烧能、高的爆轰化学能(爆热)和接近环四亚甲基四硝胺(HMX)的爆炸性能, 其对冲击敏感, 冲击感度与季戊四醇四硝酸酯(PETN)和特屈尔接近, 可用作混合炸药主组分.     

MnOx/Al-SBA-15的结构性质及低温NH3选择性催化还原NOx

采用后合成法制备MnO_x/Al-SBA-15催化剂, 考察了催化剂的低温NH₃选择性催化还原(SCR)NO_x的性能. 利用傅里叶透射红外变换(FTIR)光谱、N₂吸附-脱附、X射线衍射(XRD)、扫描电镜(SEM)、拉曼光谱(Raman)、X射线光电子能谱(XPS)及NH₃程序升温脱附(NH₃-TPD)的表征手段, 对催化剂的结构性质和SCR性能进行了系统分析. 结果表明, 适量Al的掺杂能提高MnO_x/SBA-15催化剂的SCR活性, 当硅铝摩尔比为50时, 催化剂活性最佳. 表征结果显示, Al掺杂后, 催化剂仍保持良好的骨架结构, 较大比表面、孔容和孔径, 并且Mn在催化剂表面富集, 由低价态转化为高价态, MnO₂为催化剂的主要活性相. 此外, Al的掺杂使MnO_x在催化剂表面高度分散, 表面酸性增强, 从而提高了催化剂的SCR活性.     

Ferroelectric smectic meso-phase formed by banana-shaped achiral liquid crystals

A new banana-shaped achiral molecule, 1,3-phenylene bis[4-(3-chloro-4-n-octyloxyphenyliminomethyl)benzoate] (PBCOB) has been synthesized, and its ferroelectric properties and homeotropic alignment investigated. The presence of a lateral chloro-substituent in the Schiff 's base moiety prevents the regular stacking of molecules and results in lowering the transition temperature and the degree of crystallinity of the switchable banana phase. Their smectic mesophases, including a switchable banana phase B₇, were characterized by differential scanning calorimetry, X-ray scattering and polarizing optical microscopy. Both the left- and right-handed helical domains are spontaneously formed upon cooling from the isotropic liquid to the switchable banana phase B₇. By X-ray study, the smectic phases showed a layer spacing of 38.1 Å, compatible with the end-to-end distance of the molecule with a bent conformation. Significantly, the smectic B7 phase exhibited a periodicity of 292 Å that corresponds to a helical structure with periodicity about 7.5 times 38.1 Å. The spontaneous polarization for PBCOB is about 50 nCcm^-2 and shows a temperature dependence. The ferroelectric lyomesophase of PBCOB showed a ferroelectric electro-optical switching range extending more than 50°C, switchable at room temperature.     

Crystal Structure and Thermal Stability Properties of a New 1D Chain Cu（ll） Coordination Polymer with 2,3-Pyridinedicarboxylic Acid as the Ligand

A new 1D chain copper coordination polymer [CuE（H2L）2（C10HsN2）（HEO）2]n＇3n（H20） with 2,3-pyridinedi carboxylic acid （H2L） and 2,2＇-bipyridine （2,2＇-bipy） as ligands has been synthesized in the mixed ethanol and water solvents. Crystal data for this complex are as follows： monoclinic, space group P2Jc, a = 7.7713（7）, b = 27.478（3）, c = 13.2621（13）/1,, fl = 100.6940（10）, V= 2782.8（5） A3, Dc = 1.722 g/cm3, Z = 4, p = 1.61 mm-1, F（000） = 1472, the final R = 0.0363 and wR = 0.0933. In the crystal structure, the whole molecule consists of two cooper ions, two H2L, one 2,2＂-bipy molecule and six water molecules. Each central copper ion is coordinated with three oxygen atoms from two H2L and one water molecule, two nitrogen atoms from one 2,2＇-bipy molecule and two H2L, giving a distorted tetragonal pyramidal geometry. Thermal stability properties of the complex were investigated.     

Liquid crystalline guanidinium phenylalkoxybenzoates: towards room temperature liquid crystals via bending of the mesogenic core and the use of triflate counter ions

A series of guanidinium salts 1(C _n ) _m –4(C _n ) _m ?X bearing phenyl alkoxybenzoate cores have been synthesised and their mesomorphic properties have been investigated by polarising optical microscopy (POM), differential scanning calorimetry (DSC) and powder X-ray diffraction experiments (small-angle X-ray scattering and wide-angle X-ray scattering). While compounds 1(C₁₂)₁?X and 3(C₁₂)₁?X with one alkoxy chain showed smectic A (SmA) phases irrespective of the counter ion, compounds 1(C₁₂)₂?OTf and 3(C₁₂)₂?OTf with two alkoxy chains displayed SmA phases and the corresponding chlorides 1(C₁₂)₂?Cl and 3(C₁₂)₂?Cl displayed Col_h. Guanidinium salts 1(C _n )₃–4(C _n )₃?X with three alkoxy chains showed Col_h phases. Whereas the use of cyclic guanidinium head groups rather than acyclic ones had only a minor influence on the mesophase properties, melting points were significantly decreased by bent core units instead of linear core units. Replacement of chloride counterions by triflate lead to a further depression of the clearing points and shifted the mesophase towards room temperature.     

Photochromic reverse mode polymer dispersed liquid crystals

Control of light intensity and colour are two of the major features required in the realization of smart windows. We designed a bi‐functional polymer dispersed liquid crystal (PDLC) film in order to satisfy such requirements, i.e. it is able both to modulate the optical transmission, if an external electric field is applied, and to change colour if exposed to sunlight. A monomer/liquid crystal mixture was doped with a small amount of photochromic material and homeotropically aligned by means of rough surfaces. A transparent and pale pink coloured film was achieved after photopolymerization. Such a film changes colour upon exposure for some seconds to sunlight or ultraviolet radiation in a persistent but reversible manner. In addition, the film appears transparent without the application of an electric field (OFF state) and becomes opaque on application of a driving voltage of about 75?V (ON state), and thus the film operates in reverse mode with respect to conventional PDLCs.     

Catalytic solid substrate-room temperature phosphorimetry for the determination of trace As(V) based on oxidising reaction between hydrogen peroxide and fullerenol using tween-80 as sensitizer

A new catalytic solid substrate-room temperature phosphorimetry (SS-RTP) for the determination of trace arsenic(V) has been established. It is based on the fact that fullerenol (F-ol) emitted strong and stable room temperature phosphorescence (RTP) on nitric acid cellulose membrane (NCM) substrate. H₂O₂ could oxidise F-ol to cause the quenching of RTP. As(V) could catalyse H₂O₂ to oxidise F-ol and decrease the RTP signal of F-ol sharply. After adding tween-80 in the system, its ΔI _p enhanced 7.7 times compared with the without-tween-80 levels. Under the optimum conditions, the linear dynamic range of this method was 0.016?11.2 ag spot^?1 with a detection limit (LD) of 9.3 zg spot^?1 (corresponding concentration: 2.3 × 10^?17 g mL^?1). This sensitive, simple and selective method has been successfully applied to the determination of trace As(V) in human hair and tea samples. The reaction mechanism for SS-RTP is also discussed.     

2-羰基丙酸（芳甲酰基）腙二（2,4-二氯苄基）锡配合物的合成、晶体结构、热稳定性及与DNA相互作用研究

在含水甲苯中,2,4-二氯苄与锡粉反应合成了二（2,4-二氯苄基）二氯化锡,将其分别与2-羰基丙酸（苯甲酰基）腙及2-羰基丙酸（水杨酰基）腙反应,合成了2个取代苄基锡配合物（C2、C3）,配合物C2和C3通过元素分析、¹H NMR、¹³C NMR、IR、UV-Vis等表征,运用X-射线单晶衍射测试了2个有机锡配合物的分子结构,结构分析表明,锡与配位原子形成变形五角双锥构型的双核有机锡配合物,分子以Sn₂O₂四元环为中心对称。热分析结果表明,在空气氛下,配合物C2在121℃、C3在128℃以下可稳定存在;在Tris-HCl缓冲溶液中,以EB做为荧光探针,用荧光光谱法初步研究了配合物与鲱鱼精DNA的相互作用,结果表明配合物与鲱鱼精DNA作用是插入结合与静电结合共同作用所致。     

结构稳定的CuO/TiO2纳米管的功能化溶胶修饰法制备及其催化CO氧化性能研究

以水热处理方法得到的钛酸纳米管为载体,采用含有醋酸铜的功能化钛溶胶对其进行一步浸渍修饰,制备结构稳定的CuO修饰TiO₂纳米管催化剂(CuO/TiO₂NTs)。通过XRD(X-射线衍射)、TEM(透射电子显微镜)、HR-TEM(高倍透射电子显微镜)、XPS(X-射线光电子能谱)、BET(氮气吸附-脱附法)、TPD(程序升温脱附法)等表征材料的结构和性质,并研究其催化CO氧化的性能。研究表明：经过溶胶浸渍处理过程,不仅将功能化铜组分负载在纳米管上,而且纳米管载体的耐热性能明显提高;催化剂载体、铜钛原子比及焙烧温度对催化剂的活性有明显影响,且400℃焙烧的Cu/Ti原子比为1∶5的CuO/TiO₂NTs的活性最高。     

扫帚状氧化铈制备及其对Pt基阳极催化剂催化性能的影响

采用水热合成法,合成了比表面积为175 m²·g^-1,孔径在2~4nm范围内的扫帚状CeO₂。通过微波辅助乙二醇还原氯铂酸法制备了Pt-CeO₂/RGO催化剂,探究扫帚状CeO₂的添加对Pt基催化剂电催化性能的影响。利用X射线衍射仪（XRD）、扫描电镜（SEM）、N₂吸附-脱附、X射线光电子能谱（XPS）对所制备的CeO₂及催化剂进行表征。利用电化学工作站对催化剂进行电化学性能测试。结果表明,催化剂中CeO₂保持原有扫帚状,Pt纳米粒子均匀分布于石墨烯载体表面;当m_RGO∶m_CeO2=1∶2时,添加了扫帚状CeO₂的Pt-CeO₂/RGO催化剂的电催化性能最优,电化学活性表面积为102.83 m²·g^-1,对乙醇氧化的峰值电流密度为757.17 A·g^-1,1 000 s的稳态电流密度为108.17 A·g^-1,对乙醇催化氧化反应的电荷转移电阻最小,活化能最低。